Dynamic susceptibility data static susceptibilities

With these characteristics of relaxation in normal metals in mind, let us now consider the behavior of the dynamic, nonuniform susceptibility in a low-density metal approaching the critical region. It follows from the foregoing discussion that, within the Stoner model, the Korringa ratio T7 should decrease as the static enhancement increases. This can be tested directly with the NMR data for cesium. It is evident in Fig. 3.6 that the prediction of the Stoner model is not borne out—17 increases in the low-density region where the static susceptibility enhancement also increases. Thus, we are again led to the conclusion that the susceptibility enhancement in the low-density metal is of a fundamentally different character than that of the normal, dense metal near T . 

NpFc2 and NpNi2 are established FM (with Tq =492 and 32 K). The magnetic ground state of NpCo2, in contrast, has been under some discussion. Usually it is listed as an AFM with 7n = 13 K, based on susceptibility and mainly on Mossbauer data (Aldred et al. 1975, Sanchez et al. 1992). There a Zeeman pattern appears (in the absence of an applied field) below 13 K. The spectrum shows, however, rather wide resonance lines and a clear distinction between static (distribution of internal fields) and dynamic broadening cannot... 

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